Strong nuclear interaction

The strong nuclear force is of interest in both nuclear and particle physics. The strong force is one of the four fundamental interactions. The others are gravity, electromagnetism and the weak force. 

The strong nuclear force holds ordinary matter together.  It confines quarks into hadron particles. For example, the proton and neutron. A proton is two up quarks and a down quark while a neutron is two down quarks and an up quark. The strong force also acts to bind these protons and neutrons into atomic nuclei. Individual quarks make up about 1% of the mass of the proton. The rest of the mass is the result of the strong force field energy.